/* ============================================================
   RAD Engineering — styles.css
   Aesthetic: clean technical / engineering
   Type:      IBM Plex Sans + IBM Plex Mono
   Palette:   Navy #2B3D51 / Cyan #4BC9EF / off-white #FAFAF8
   ============================================================ */

:root {
  --c-bg:        #FAFAF8;
  --c-bg-alt:    #F4F4F1;
  --c-ink:       #1A1F2A;
  --c-ink-soft:  #4A5462;
  --c-muted:     #8A93A1;
  --c-rule:      #E5E5E1;
  --c-navy:      #2B3D51;
  --c-navy-dark: #1F2D3C;
  --c-cyan:      #4BC9EF;
  --c-cyan-dark: #2BB3DC;

  --ff-sans: 'IBM Plex Sans', system-ui, -apple-system, sans-serif;
  --ff-mono: 'IBM Plex Mono', ui-monospace, Menlo, monospace;

  --container-max: 1180px;
  --container-pad: clamp(20px, 4vw, 48px);

  --radius: 2px;
  --transition: 220ms cubic-bezier(0.4, 0, 0.2, 1);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  background-color: var(--c-bg);
}

body {
  margin: 0;
  color: var(--c-ink);
  font-family: var(--ff-sans);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(43, 61, 81, 0.06) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(43, 61, 81, 0.06) 1px, transparent 1px),
    linear-gradient(to right, rgba(43, 61, 81, 0.015) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(43, 61, 81, 0.015) 1px, transparent 1px);
  background-size: 48px 48px, 48px 48px, 12px 12px, 12px 12px;
  -webkit-mask-image: radial-gradient(ellipse 65% 70% at 50% 50%, #000 0%, rgba(0, 0, 0, 0.17) 100%);
  mask-image: radial-gradient(ellipse 65% 70% at 50% 50%, #000 0%, rgba(0, 0, 0, 0.17) 100%);
}

img, svg { max-width: 100%; height: auto; display: block; }

a { color: inherit; text-decoration: none; }

::selection { background: var(--c-cyan); color: var(--c-navy); }

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding-left: var(--container-pad);
  padding-right: var(--container-pad);
}

/* ============================================================
   HEADER / NAV
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(250, 250, 248, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--c-rule);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1;
}
.brand-rad {
  color: var(--c-navy);
  font-size: 22px;
  font-weight: 800;
  letter-spacing: -0.02em;
}
.brand-eng {
  color: var(--c-cyan);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0;
}

.site-nav {
  display: flex;
  gap: 32px;
  font-family: var(--ff-mono);
  font-size: 13px;
  font-weight: 500;
}
.site-nav a {
  color: var(--c-ink-soft);
  position: relative;
  padding: 4px 0;
  transition: color var(--transition);
}
.site-nav a:hover { color: var(--c-navy); }
.site-nav a::after {
  content: '';
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 1px;
  background: var(--c-cyan);
  transition: width var(--transition);
}
.site-nav a:hover::after { width: 100%; }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  position: relative;
  overflow: hidden;
  padding: clamp(72px, 14vh, 140px) 0 clamp(80px, 14vh, 140px);
  background: transparent;
}

.hero-inner {
  position: relative;
  z-index: 1;
}

.eyebrow {
  font-family: var(--ff-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--c-ink-soft);
  margin: 0 0 28px;
  display: inline-flex;
  align-items: center;
  gap: 12px;
}
.eyebrow::before {
  content: '';
  width: 32px; height: 1px;
  background: var(--c-cyan);
  display: inline-block;
}

.hero-title {
  font-family: var(--ff-sans);
  font-weight: 700;
  font-size: clamp(32px, 6vw, 68px);
  line-height: 1.05;
  letter-spacing: -0.025em;
  color: var(--c-navy);
  margin: 0 0 28px;
  text-wrap: balance;
}

.accent { color: var(--c-cyan); }

.hero-sub {
  font-size: clamp(16px, 1.6vw, 19px);
  line-height: 1.55;
  color: var(--c-ink-soft);
  max-width: 56ch;
  margin: 0 0 40px;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 24px;
  font-family: var(--ff-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.04em;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}
.btn-primary {
  background: var(--c-navy);
  color: var(--c-bg);
}
.btn-primary:hover {
  background: var(--c-navy-dark);
  transform: translateY(-1px);
}
.btn-ghost {
  background: transparent;
  color: var(--c-navy);
  border-color: var(--c-navy);
}
.btn-ghost:hover {
  background: var(--c-navy);
  color: var(--c-bg);
}

/* ============================================================
   SECTIONS
   ============================================================ */
.section {
  padding: clamp(80px, 12vh, 140px) 0;
  transition: opacity 600ms ease-out, transform 600ms ease-out;
}
/* Only hide sections when JS is available (progressive enhancement) */
.js-ready .section {
  opacity: 0;
  transform: translateY(16px);
}
.js-ready .section.in-view {
  opacity: 1;
  transform: translateY(0);
}
.section-alt {
  border-top: 1px solid var(--c-rule);
  border-bottom: 1px solid var(--c-rule);
}

.section-label {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 32px;
  font-family: var(--ff-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-ink-soft);
}
.label-num { color: var(--c-cyan); }
.label-rule {
  flex: 0 0 56px;
  height: 1px;
  background: var(--c-navy);
}
.label-text { color: var(--c-navy); }

.section-title {
  font-family: var(--ff-sans);
  font-weight: 700;
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--c-navy);
  margin: 0 0 56px;
  max-width: 22ch;
}

/* ============================================================
   ABOUT
   ============================================================ */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: clamp(40px, 6vw, 96px);
  align-items: start;
}
.about-grid .section-title { margin-bottom: 0; }
.about-body p {
  margin: 0 0 20px;
  font-size: 17px;
  line-height: 1.7;
  color: var(--c-ink-soft);
}
.about-body p:last-child { margin-bottom: 0; }

@media (max-width: 768px) {
  .about-grid { grid-template-columns: 1fr; }
  .about-grid .section-title { margin-bottom: 0; }
}

/* ============================================================
   SERVICES
   ============================================================ */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border-top: 1px solid var(--c-rule);
  border-left: 1px solid var(--c-rule);
}

.service-card {
  position: relative;
  padding: 36px 32px 40px;
  border-right: 1px solid var(--c-rule);
  border-bottom: 1px solid var(--c-rule);
  min-height: 260px;
}
.service-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 0;
  height: 2px;
  background: var(--c-cyan);
  transition: width 320ms cubic-bezier(0.4, 0, 0.2, 1);
}
.service-card:hover::before { width: 100%; }

.service-head {
  position: absolute;
  left: 32px;
  right: 32px;
  top: 50%;
  transform: translateY(-50%);
  transition: top 360ms cubic-bezier(0.4, 0, 0.2, 1),
              transform 360ms cubic-bezier(0.4, 0, 0.2, 1);
}

.service-num {
  font-family: var(--ff-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--c-cyan);
  margin-bottom: 18px;
}
.service-title {
  font-family: var(--ff-sans);
  font-weight: 600;
  font-size: 21px;
  line-height: 1.25;
  letter-spacing: -0.015em;
  color: var(--c-navy);
  margin: 0;
}
.service-body {
  margin: 96px 0 0;
  font-size: 15.5px;
  line-height: 1.6;
  color: var(--c-ink-soft);
}

@media (hover: hover) {
  .service-body {
    opacity: 0;
    transform: translateY(6px);
    transition: opacity 260ms ease 120ms, transform 260ms ease 120ms;
  }
  .service-card:hover .service-head,
  .service-card:focus-within .service-head {
    top: 36px;
    transform: translateY(0);
  }
  .service-card:hover .service-body,
  .service-card:focus-within .service-body {
    opacity: 1;
    transform: none;
  }
}

@media (hover: none) {
  .service-head {
    position: static;
    transform: none;
  }
  .service-body {
    margin-top: 12px;
  }
}

.service-card:focus-visible {
  outline: 2px solid var(--c-cyan);
  outline-offset: -2px;
}

@media (max-width: 900px) {
  .services-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .services-grid { grid-template-columns: 1fr; }
}

/* ============================================================
   PARTNERS
   ============================================================ */
.partners-row {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
}

.partner {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 140px;
  padding: 32px 24px;
}

.partner a {
  display: inline-block;
  transition: opacity var(--transition);
}
.partner a:hover { opacity: 0.65; }

.partner img {
  max-height: 56px;
  max-width: 180px;
  width: auto;
}

@media (max-width: 700px) {
  .partners-row { grid-template-columns: 1fr; }
}

/* ============================================================
   CONTACT
   ============================================================ */
.section-contact {
  background: var(--c-navy);
  color: var(--c-bg);
  position: relative;
  overflow: hidden;
}
.section-contact .label-text { color: var(--c-bg); }
.section-contact .label-rule { background: var(--c-bg); }
.section-contact .section-title {
  color: var(--c-bg);
  max-width: 24ch;
  font-size: clamp(25px, 3.6vw, 40px);
}

.contact-lede {
  font-size: 18px;
  line-height: 1.6;
  color: rgba(250, 250, 248, 0.72);
  max-width: 56ch;
  margin: 0 0 48px;
}

.contact-email {
  display: inline-block;
  font-family: var(--ff-sans);
  font-weight: 600;
  font-size: clamp(22px, 4vw, 42px);
  letter-spacing: -0.025em;
  color: var(--c-bg);
}
.contact-email .ci {
  position: relative;
}
.contact-email .ci::after {
  content: '';
  position: absolute;
  top: 0.23em;
  left: 50%;
  width: 0.18em;
  height: 0.18em;
  border-radius: 50%;
  background: currentColor;
  transform: translateX(-50%);
  transition: background var(--transition);
}
.contact-email .accent {
  transition: color var(--transition);
}
.contact-email:hover .ci::after {
  background: var(--c-cyan);
}
.contact-email:hover .accent {
  color: var(--c-bg);
}

.contact-meta {
  margin-top: 56px;
  font-family: var(--ff-mono);
  font-size: 13px;
  letter-spacing: 0.056em;
  word-spacing: -0.4em;
  color: rgba(250, 250, 248, 0.5);
  text-transform: uppercase;
}

/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  background: var(--c-navy-dark);
  color: rgba(250, 250, 248, 0.6);
  padding: 36px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}
.footer-brand .brand-rad { font-size: 18px; }
.footer-brand .brand-eng { font-size: 12px; }
.footer-copy {
  margin: 0;
  font-family: var(--ff-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
}

/* ============================================================
   MOBILE NAV
   ============================================================ */
@media (max-width: 640px) {
  .site-nav { gap: 16px; font-size: 12px; }
  .site-nav a:nth-child(3) { display: none; } /* hide Partners on small screens */
}

/* ============================================================
   REDUCED MOTION
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  .section { opacity: 1; transform: none; }
  html { scroll-behavior: auto; }
}